I started this thread with the opinion that some aeration, even if it is less than recommended amounts, is better than no aeration. I do not know that my opinion on that has changed, but I do have an observation over the last year that has shown me that inadequate aeration does have negative side effects. Or at least that is what I think I have learned. Who knows for sure based only on anecdotal evidence.
In the last few years in the heat of summer I have had some issues with bluegreen algae otherwise known as cyanobacteria. This was with aeration using three linear air pumps and three double diffusers in a three acre pond. The pumps were barely adequate to create decent air flow to the 8-10' depths encountered.
This year I installed a rotary vane pump
GAST 1023 rotary vane pump upgrade installation to drive all three of the double diffusers with one pump. The single large pump puts out much, much more air than the three independent linear air pumps and subsequently I have put it on a timer and only run it 8-10 hours per day (kind of depending on the temperature and time of year - still an ongoing search for the best combination). This year I have had almost no problem with the bluegreen algae blooms. Till the other day. I was just starting to get some floating to my north shore line from a south wind. I kicked on the air pump and let it run 24-7. The visible algae bloom went away (probably mixed in) within hours.
It appears (anecdotal evidence only) that by increasing the aeration and water turn over it changed conditions to disfavor the bluegreen algae bloom.
I would be interested in others comments or experiences on this observation. It looks like to me I need to set my timer for a little more aeration in the current summer conditions. Also noteworthy is that we have had recent rains and new water flowing into the pond through the sediment pond which has a high nutrient load. So some new nutrient laden water could have been the cause of the bloom. At any rate increased aeration seems to have changed conditions enough to discourage the bluegreen algae bloom.
PBF get together September 22, 2018 SE Kansas 
